Burner for gaseous fuel



1966 E. G. A. GEBER 3,289,731

BURNER FOR GASEOUS FUEL Filed Aug. 5, 1963 United States Patent 3,289,731 BURNER FOR GASEOUS FUEL Ernst Gustav Arvitl Geber, Sundbyberg, Sweden, assignmto Ahtieholaget Max Sievert, Sundhyherg, Sweden, a corporation of Sweden Filed Aug. 5, 1963, Ser. No. 303,205 1 Claim. (61. 158-116) This application is a continuation-in-part of co-pending application Serial No. 89,248, filed February 14, 1961, and now abandoned.

This invention relates to burners for gaseous fuels and, more particularly, to such burners constructed and adapted for use out of doors and to resist being blown out by wind and for use with a supply of relatively high pressure gaseous fuel requiring both primary and secondary combustion air.

In contrast with conventional gas burners for domestic cook stoves, and the like, for use indoors in a kitchen and where the fuel gas is supplied to the burner at relatively low pressures, gas burners for use in outdoor cooking, as on picnics or camping trips, should be arranged to avoid having one or more of the individual flames blown out by whatever breeze or wind may occur, particularly if the burner is unprotected. To this end, such a gas burner may be constructed to provide a continuous annular flame or flame ring, instead of individual widely spaced flames as in the conventional kitchen stove burner, with the individual gas-air mixture jets or streams emanating from closely spaced holes to form, upon ignition, a continuous annular flame. In this manner, momentary blowing out of a part of the flame ring may occur, but the blown out jets will be immediately reignited if only by virtue of the close proximity of adjacent portions of the continuous ring of flame.

Also, with such picnic-type burners for outdoor use, it may be desired that the burner be attached directly to a small bottle or tank of propane or other fuel gas, and without the interposition of complicated or bulky pres sure reducing valves, etc., in which event the fuel gas will be supplied to the burner at relatively high pressures (e.g., more than 1 kg./cm. and frequently at 5-9 kg./cm. well above the gas line pressure of the conventional gas burner. Whether or not the foregoing high pressure supply be considered merely as a matter of convenience with a portable burner or a further aid to preventing extinguishment of the flame by wind, etc., such high pressure supply of fuel or a fuel-air mixture may produce the result, particularly in a continuous flame burner, of creating an extremely intense flame, and certainly produces the result that complete combustion is not to be expected merely from the primary air admixed with the gaseous fuel, so that additional secondary air is necessary to be supplied adjacent the flame from a source other than the fuel gas supply from within the burner.

If all the foregoing disparate factors are attempted to be coordinated into a single construction having closely spaced gas ports to provide a continuous and self-spreading flame ring or continuous annular flame and the high pressure gas supply noted, substantial difliculty may be experienced in providing sufiicient secondary combustion air to the flame ring and, particularly, in the center of the ring. For example, particularly when a cooking vessel is above the burner so that the continuous flame ring impinges directly on the bottom of the vessel closing off the air space within the flame ring, the secondary air available within the ring of flame may be insufficient for complete combustion. Even without a cooking vessel positioned above the burner, with such high pressure fuel supply, the flame ring may be so intense as to enclose the entire space within the ring in a wall or dome of flame which prevents secondary air from access to the interior of the flame ring.

If, on the other hand, the intensity or continuity or solidity of the flame ring is to be diminished by more widely spaced ports or openings therein, the desired continuous ring of flame may not be obtained, particularly on a windy da regardless of how much such arrangement may enhance the introduction of secondary air to the inside of the flame ring. If suflicient secondary air is not introduced into the flame ring, on the other hand, complete combustion will not occur and to an extent in which an excessive amount of carbon monoxide is produced as a combustion product to even a dangerous or toxic extent in the area immediately adjacent the burner.

According to this invention, however, a burner construction is provided in which a continuous annular flame or flame ring is maintained from closely spaced gas ports so that any potrion of the ring which is momentarily extinguished or blown out by wind will be immediately reignited by adjacent ports; while also being adapted to accommodate relatively high pressure gas feeds, even to the point of forming a virtually impenetrable flame ring requiring secondary air for complete combustion at the inside of the ring; and such secondary air is supplied into the ring, even when a cooking vessel is positioned above the burner, by one or more deliberate interruptions in the otherwise continuous flame ring and throughout only a tiny portion of the circumferential extent thereof for admission of secondary air.

With the foregoing and additional objects in view, this invention will be explained in more detail, and other objects and advantages thereof Will be apparent from the following description, the accompanying drawing, and the appended claim.

In the drawing:

FIG. 1 is a longitudinal sectional view along the line II of FIG. 2 of a burner construction embodying and for practicing this invention; and

FIG. 2 is a top plan view of the burner construction shown in FIG. 1.

As will be understood, with ring-type gas burners generally, if there is an opening in the central portion of the burner ring, little difficulty is experienced in supplying adequate secondary air to the flames, even if the individual flames unite to form a substantially continuous and enclosing flame ring. If no such central opening is provided (as when it is desired to supply air-gas mixture into the burner at the center thereof for uniform radial distribution to all flame ports around the outside of the ring), the burner top or cap may not have a central opening, so that secondary air may only enter the space Within the ring of flames by passing between adjacent flames, especially when the space above the burner V is limited by the bottom of a utensil placed thereover. With high pressure fuel supply and/or closely spaced flame ports arranged to provide a continuous flame ring, instead of a ring of separated individual flames, the continuous flame forms not only a continuous vertical circumferential wall of flame around the burner reaching all the way to the bottom of a utensil placed thereover, but also may form a continuous dome of flame over the burner even when the utensil is in use. It is particularly in this situation where, according to this invention, an opening or secondary air entrance is provided in the burner ring (by eliminating or blocking off a few of the flame ports at one point in the periphery of the burner) to permit free entrance of secondary air to the inside of the continuous flame ring.

Thus, referring to the drawings, in which like reference numerals refer to like parts throughout the several views thereof, a threaded fitting 10 having a gasket 12, is provided for screw connection to the outlet of a bottle of pressurized gaseous fuel, such as propane, for supplying to the burner. After passing a wire mesh screen 14, the gas is ejected from a nozzle 16 provided with fine discharge openings, and through a burner pipe 18 threaded to fitting 10, all in known manner. An enlarged airmixing device having primary air openings 20 is provided at the bottom part of burner pipe 18, for the admixture of primary combustion air with the gaseous fuel as it passes [from nozzle 16 up through pipe 18, again all in known manner.

In the embodiment illustrated, the burner ring itself is in the form of an inverted bowl or truncated cone which may readily be fabricated merely from two sheet metal sta-mpings. Thus, a bottom bow-l 22 is provided and afiixed to the upper end of pipe 18, and carries burner cap 24 disposed with respect to bowl 22 as shown to provide a substantially uniform annular passage 26 therebetween. The burner cap 24 has a raised central portion 34 for supporting a cooking vessel placed thereon. The outermost conical surface 28 of burner cap 24 are provided with a multiplicity of fine flame ports 3t), preferably arranged in several rows and extending all around the periphery of surfaces 23 with the exception of a small section indicated as 32 in FIG. 2.

In operation of the burner, fuel gas is discharged through nozzle 16 and mixes with primary air entering through the apertures 20 in burner pipe 18. The gasair mixture moves upwardly in pipe 18 into the space 26 between bottom bowl 22 and burner cap 24, and is distributed within the burner to the various flame ports 30, through which the mixture exits upon ignition to form a continuous ring of flame around the burner. As will be noted, the arrangement of spacing of burner ports 30 is such that the distance between adjacent ports 30 is of the same general order of magnitude as the diameter of the ports, rather than being many times the diameter of the ports as in other types of burners. In this manner, the individual streams of fuel-air mixture leaving the dif ferent ports 30 mingle with each other after ignition to form the continuous flame ring desired, with the result that, should the flame get extinguished at any particular opening 30, reignition will occur almost at once from the flames at adjacent openings 38. Especially with high pressure gas feeds as noted, the length or height of the flame is usually so great that the continuous ring or wall of flame goes around the burner and even up over the top thereof to enclose the space above the central portion of the burner and within the ring, especially if a utensil is positioned over the burner, in a manner to inhibit the entrance of secondary air necessary for complete combustion.

As indicated, there is provided an area 32 at one part of the conical face 28 of the burner where there are no flame ports 30, this providing an entrance or flame-free area for the admission of secondary air into the inside of the flame ring above cap 24. In this manner, relatively complete combustion is achieved because the flame ring has free access to secondary air around the outside thereof, and additional secondary air enters into the inside of the ring through the flame-free opening therein adjacent area 32. Nevertheless, throughout the entire rest of the periphery of the burner, the flame is actually a continuous ring with the above noted advantages thereof, such as immediate reignition upon extinguishr'nent at one portion or another, etc.

The question of secondary air, of course, becomes important especially with high pressure gas supply, such as here, and is necessary to achieve complete conversion of carbon monoxide. For example, considering propane as the gaseous fuel, primary combustion with the primary air admixed with the fuel gas in pipe 18 occurs according to the following equation:

while secondary combustion occurs with secondary air at the actual flame points, according to the following:

As a general rule of thumb, the carbon monoxide content of exhaust gases from such a combustion should not exceed 0.01% by volume in any space or area where a human being is to be situated for any substantial length of time (e.-g., 8 hours), but, even out of doors, excess carbon monoxide production immediately adjacent the burner is certainly not to be desired.

With the imperforate area 32 provided, free access of secondary air is permited into the space above the burner cap 24 and within the ring of flame and even when enclosed by a cooking utensil placed above the burner onto the bot-tom of which the ring of flames may impinge. As will be understood, the imperforate area 32 may be provided at the time of making the burner cap 24, or, if perforations 30 are all around burner cap 24, an imperforate area 32 is readily achieved by placing a plate or similar member over some of the openings 30. The invention is also applicable to such structures where one or more continuous burner rings or supply spaces 26 are disposed between an upper burner cap and a lower bowl or pipe, which spaces are then blocked off within the burner structure at one point in order to provide a flamefree area for entrance of secondary air to within the flame ring notwithstanding that the flame ring is otherwise continuous.

As will be apparent from the foregoing, there is pro vided in accordance with this invention a gas burner adapted to achieve a continuous and self-spreading flame around the sides thereof, but with at least one gap therein for the introduction of secondary air into the inside of the ring of flame. Such secondary air not only enhances and completes the combustion of fuel gas, but also produces some cooling effect on burner cap 24 as a means of extending the service life thereof. A Some What better and faster combustion of fuel gas by having plenty of secondary air also tends to produce a slightly shorter flame, even with high pressure gas feeds, thus providing a better utilization of heat by a cooking vessel placed over the burner and avoiding the risk that the flame may be so long or high as to extend beyond the outside of the cooking vessel and thus waste the fuel to no purpose. In this manner complete and enhanced combustion is achieved in a structure which is also capable of providing the additional but independent advantages of a continuous and self-spreading flame for outdoor use where accidental ex-tinguishment of any portion of the flame is immediately corrected by immediate reignition from adjacent flame ports.

While one or more or less specific embodiment of the invention has been shown and described, it is to be understood that this is for purposes of illustration only and that the invention is not limited thereby, but its scope it to be determined by the appended claim.

What is claimed is:

In high pressure windproof gas burner apparatus adapted for direct connection to a bottle of pressurized fuel gas, the combination which comprises a feed pipe including primary air mixing means for feeding an airgas mixture to said burner and disposed substantially in the center thereof, two interfitting and spaced frustroconical plates forming a bowl-shaped burner member with a substantially flat top and downwardly and outwardly extending sides, said feed pipe being in flow communication with the space between said plates for feeding said air-gas mixture thereinto, a large plurality of small and closely spaced discharge openings in said sides of the outer of said plates for combustion of said air gas mixture upon discharge through said openings whereby a continuous ring of flame is provided around said burner with the combustion through each said opening merging with that through adjacent openings into said continuous flame ring, said discharge openings :being disposed in a plurality of staggered rows with the spaces between adjacent said opening being substantially no :greater than the diameter of each said opening a single area in said sides devoid of said holes for interrupting said otherwise oontinuous flame ring around said burner permitting secondary combustion air to flow into said continuous flame ring through said interrupted area, and a raised central portion on said flat top of said burner member for spacing the bottom of a cooking vessel resting thereon a'bove edge portions of said burner permitting secondary air entering said flame ring through said interrupted area to flow Ibeneath said vessel through all angular portions around said burner and within said flame ring.

References Cited by the Examiner UNITED STATES PATENTS FOREIGN PATENTS 1/1954 France,

FREDERICK L. MATTESON, JR., Primary Examiner. 

